After ultraviolet light irradiation, strain 6464 of Bacillus cereus lysed, resulting in the release of toxin, phospholipase, and mature phage particles. Small amounts of toxin and phospholipase produced by non-induced cultures were correlated with the infrequent spontaneous release of bacteriophage. Stationary incubation following ultraviolet induction results in a greater yield of toxin and phospholipase than post irradiation incubation on a shaker. Post-irradiation incubation at temperatures below 37C either reduced (30C) or prevented (26C) toxin and phospholipase production. A clone was obtained which was sensitive to the phage from the parent strain and was presumably no longer lysogenic for it. This cured strain still exhibited ultraviolet-induced optical density decline accompanied by release of toxin and phospholipase. Mitomycin C would induce strain 6464 and the cured strain derived from it and both released toxin and phospholipase during mitomycin C induced lysis. The induced lysis of the cured strain could be prevented by postinduction treatment with inhibitors of synthesis of protein (chloramphenicol), RNA (actinomycin D), or DNA (5-fluorouracil deoxyriboside).

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